Axial flow booster pump



Dec. 30, 1969 H 5, 553m ET AL 3,486,457

AXIAL FLOW BOOSTER PUMP Filed March 1, l9 5 Sheets-Sheet. 1

\\\ \,i/ F l I l I 26 -l8 4 INVENTORS ALFRED B. SABIN BY JAMES w. CASTEN ATTORNEYS Dec. 30, 1969 A. B. SABIN T AL 3,486,457.

AXIAL FLOW BOOSTER PUMP Filed March 1, 1968 5 Sheets-Sheet 2 7| 94 \462 96 I v I 93 F 2 /40 86 85 'v r F/G. 3 97 l L 505 I F/ 5' I INVENTORS.

ALFRED B. SABIN BY JAMES W. CASTEN nu. M0142, Mu W ATTORNEYS Dec. 30, 196-9 E A. B. SABIN E1 AL 3,486,457

AXIAL FLo'w BOOSTER PUMP Filed March 1, 1968 S Sheets-Sheet 5 INVENTORS ALFRED B. SABIN JAMES W. CASTEN #4.. M4,,m Mv #Jut ATTORNEYS United States Patent U.S. Cl. 103-89 4 Claims ABSTRACT OF THE DISCLOSURE An axial flow :booster pump for installation in process equipment such as evaporators to circulate high COIlSlS- tency pulp.

BACKGROUND OF THE INVENTION This invention relates generally to an axial flow booster pump adapted to be installed within a process vessel to enhance circulation of pulp and make possible the processing of high consistency pulp in equipment otherwise designed to handle only medium-high-solid pulps.

An example of process equipment of the type in which the invention is useful are vertical tube or rising film evaporators. Thin solutions evaporate very rapidly in a rising film evaporator due to the high velocities created by the vapor produced. As consistency increases, circulation and resulting evaporation drop.

Present design of vertical tubes evaporators permits concentration of food products such as tomato paste by thermally induced circulation to about 26% solids. This capability can be increased to 32% solids or higher by use of a booster pump to maintain circulation. It is possible to install a booster pump separately and connect it to the equipment by pipes. Installation of such a separate pump involves considerable time, expense and space. In other instances, a high consistency type evaporator is employed. Generally, such evaporators are expensive as to initial cost, installation, operation and maintenance and make it diflicult to convert back to the original natural circulation when it is desired to process low solid materials in the evaporator.

SUMMARY OF THE INVENTION AND OBJECTS The booster pump assembly of the present invention includes a driven shaft mounted in an oil filled housing which includes bearings and seals. The housing and shaft are supported at one end by a flange adapted to be attached to the process equipment and at the other end by a spider adapted to fit within the circulating outlet pipe. The pump assembly also includes an entrance cone for directing flow of the pulp through the propeller and a straightening means for changing rotary to linear velocity and reducing turbulence of the pulp.

It is a general object of the present invention to provide a booster pump suitable for use within process equipment.

It is another object of the present invention to provide a booster pump which can be mounted in an evacuated enclosure with externally mounted power means.

It is another object of the present invention to provide a pump which can be used to maintain high rates of circulation for high consistency materials to achieve high rates of evaporation.

It is a further object of the present invention to prevent cavitation of pulp entering the propeller.

It is a further object of the present invention to provide a booster pump which is designed for easy installation and removal from process equipment.

The foregoing and other objects of the invention will 3,486,457 Patented Dec. 30, 1969 "ice become more clearly apparent from the following description taken in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is an elevational view of an evaporator incorporating a booster pump in accordance with the present invention.

FIGURE 2. is a bottom view, partly in section, taken along the line 22 of FIGURE 1.

FIGURE 3 is a sectional view taken generally along the line 33 of FIGURE 2.

FIGURE 4 is an enlarged view of the portion 4-4 of FIGURE 3.

FIGURE 5 is an enlarged view of the portion 5--5 of FIGURE 3.

FIGURE 6 is a view taken generally along the line 66 of FIGURE 2.

FIGURE 7 is a view taken generally along the line 77 of FIGURE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGURE 1, there is shown a support structure including uprights 11 and across members 12 which support the evaporator assembly 13. It is, of course, understood that the supporting framework may be of other design and that the framework shown is merely illustrative.

The evaporator includes a steam chest section 18 including a plurality of spaced vertical tubes 19. The tubes 19 receive the pulp at the lower end 21. The pulp moves upwardly through the tubes where it is heated by the steam surrounding the tubes. As the pulp is heated and the water evaporates and forms steam, the pulp and steam issue from the top of the tubes and flow into the separator section 22. The steam causes a pumping action to induce circulation of pulp into and through the tubes.

Separator section 22 is connected by pipe 23 to the separator 24 secured at the upper end of leg 26. The pulp products flow downwardly through the leg 26 and into the separator section through the pipe 27. A vacuum is applied to the trap at 25 to withdraw the steam and non-condensables from the separator 24. The concentrated pulp products flow downwardly in the leg 26 across pipe 27 to the chamber 28 at the bottom of the separator section. When the pulp is of desired consistency, it can be removed at the outlet 29. Additional pulp can be introduced into the system through the inlet 31.

In accordance with the present invention, there is provided a booster pump assembly 33 driven by motor 34 mounted on support 36. The drive means shown includes belts 37 which engage the pulleys 38 and 39.

The pulley 38 is mounted on the shaft 40 journalled between outer bearing 41 and inner bearing 42, FIG- URES 2-6. The bearing 42 is carried in the ring 43 fitted into the shaft housing or tube 44. The other end of the housing is secured to flange 46 and bearing support flange 47 as by welding.

An inner seal assembly 48 is disposed within the ring 43 to seal the inside of the housing 44 from the evacuated interior of the process equipment. The seal assembly includes spaced rings 49 and 50 urged apart by a spring 51. The inclined edge of ring 50 bears against an inclined edge of annular seal 52 to urge it against the shaft. The other edge of annular seal 52 is urged against the inclined edge of ring 53 held by seal assembly retainer 54. The ring 53 and seal assembly 48 are held by a plate 56 threadably received by the end of housing 44. A sleeve, 57 protects the end of the shaft against corrosion, permitting use of a carbon steel shaft for strength and economy.

An outer seal assembly 61 is provided at the other end of the shaft and comprises spaced rings 62 and 63 urged apart by means of a spring 64. An annular seal 65 is adapted to fit between the ring 63 and an outer seal ring assembly 66 to urge the seal 65 against the shaft. Plate 67 is secured to flange 47 and retains the seal assembly.

The space 73 between the shaft 39 and housing 44 is filled with oil. The oil level is maintained by means of an oil reservoir 71 which communicates through tube 72 with the space 73. The seals not only retain the lubricating oil, but also provide a vacuum seal whereby there there is no leakage through the assembly into the processing equipment. A drain 75 is provided for draining the oil when it needs changing.

The inner end of housing 44 is supported by a spider 81 accommodated in the pipe section 82. Locking screw 83 extends through the pipe to engage one fin of the spider. Referring particularly to FIGURE 6, the spider is in the form of three fins extending radially outwardly. One fin is engaged by the screw 83 to force the remaining fins against the pipe 82 to firmly hold the end of the assembly. The fins also support concentric entrance cone 85.

Propeller 86 is threadably received by the shaft 40. Rotation of the propeller causes the pulp to move as indicated by the arrow 87, FIGURE 2. Thus, the pulp flowing downwardly in the leg 26 is induced to flow through the pipe 27 into the chamber 28 Where it flows upwardly through the vertical tubes 19. The entrance cone 85 directs the flow of pulp into the propeller 86.

Straightening vanes 90 are provided on the downstream side of the propeller. These vanes are shown carried in a separate section of pipe 89 provided with spaced flanges 91 and 92 for easy insertion and removal. The vanes change rotary motion of the pulp into linear motion and also reduce turbulence.

As previously described, the outer end of the shaft assembly is journalled in bearing 41. The bearing 41 is attached to the flange 47 by means of bolts 93. A shear plate 67 is provided for alignment.

The leg 26 is provided with flange 96 which receives and holds the pump flange 46. The flanges may be secured to one another by means of spaced bolts 97.

It is seen that the complete pump assembly can be easily removed by loosening the bolts and withdrawing the assembly from the equipment. A flat plate can then be bolted to the flange 96 and the apparatus operated in a conventional manner.

What is claimed is:

1. An axial flow pump assembly in a process equipment of the type including an outlet pipe to increase the flow of high consistency pulp comprising a shaft housing, a shaft disposed coaxially Within said housing, bearings disposed at opposite ends of said housing serving to journal said shaft, sealing means at the ends of said shaft, means for introducing a lubricant in the space between said shaft and housing, a propeller carried by said shaft adjacent one end of said housing and adapted to be immersed in the pulp to move the pulp through said outlet pipe, support vanes are carried at said one end of the housing and adapted to fit within said outlet pipe for supporting the said one end of the housing on said pipe, said support vanes also serving as suction straightening vanes, and a flange secured to the other end of said housing for supporting the housing and adapted to be secured to the process equipment to removably mount the pump assembly as a unit from within the process equipment.

2. An axial flow pump assembly as in claim 1 including a cone mounted on said vanes for directing the pulp into the propeller.

3. An axial flow pump assembly as in claim 2 including straightening vanes mounted in said pipe at the downstream end of said propeller.

4. An axial flow pump assembly as in claim 3 in which said straightening vanes are removably mounted in said pipe.

References Cited UNITED STATES PATENTS 1,082,594 12/1913 Kern 10389 1,932,881 10/1933 Bowen et a1. 103-93 2,169,232 8/1939 Flanders 230- 2,552,681 5/1951 Lang 10389 2,502,204 3/1950 Cole 230209 2,773,639 12/1956 Wheller 230209 HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 103-111 

